ZeroTierOne/core/Utils.hpp

901 lines
23 KiB
C++

/*
* Copyright (c)2013-2020 ZeroTier, Inc.
*
* Use of this software is governed by the Business Source License included
* in the LICENSE.TXT file in the project's root directory.
*
* Change Date: 2024-01-01
*
* On the date above, in accordance with the Business Source License, use
* of this software will be governed by version 2.0 of the Apache License.
*/
/****/
#ifndef ZT_UTILS_HPP
#define ZT_UTILS_HPP
#include "Constants.hpp"
#include <utility>
#include <algorithm>
#include <memory>
namespace ZeroTier {
namespace Utils {
#ifndef __WINDOWS__
#include <sys/mman.h>
#endif
// Macros to convert endian-ness at compile time for constants.
#if __BYTE_ORDER == __LITTLE_ENDIAN
#define ZT_CONST_TO_BE_UINT16(x) ((uint16_t)((uint16_t)((uint16_t)(x) << 8U) | (uint16_t)((uint16_t)(x) >> 8U)))
#define ZT_CONST_TO_BE_UINT64(x) ( \
(((uint64_t)(x) & 0x00000000000000ffULL) << 56U) | \
(((uint64_t)(x) & 0x000000000000ff00ULL) << 40U) | \
(((uint64_t)(x) & 0x0000000000ff0000ULL) << 24U) | \
(((uint64_t)(x) & 0x00000000ff000000ULL) << 8U) | \
(((uint64_t)(x) & 0x000000ff00000000ULL) >> 8U) | \
(((uint64_t)(x) & 0x0000ff0000000000ULL) >> 24U) | \
(((uint64_t)(x) & 0x00ff000000000000ULL) >> 40U) | \
(((uint64_t)(x) & 0xff00000000000000ULL) >> 56U))
#else
#define ZT_CONST_TO_BE_UINT16(x) ((uint16_t)(x))
#define ZT_CONST_TO_BE_UINT64(x) ((uint64_t)(x))
#endif
#define ZT_ROR64(x, r) (((x) >> (r)) | ((x) << (64 - (r))))
#define ZT_ROL64(x, r) (((x) << (r)) | ((x) >> (64 - (r))))
#define ZT_ROR32(x, r) (((x) >> (r)) | ((x) << (32 - (r))))
#define ZT_ROL32(x, r) (((x) << (r)) | ((x) >> (32 - (r))))
#ifdef ZT_ARCH_X64
struct CPUIDRegisters
{
CPUIDRegisters() noexcept;
bool rdrand;
bool aes;
bool avx;
bool vaes; // implies AVX
bool vpclmulqdq; // implies AVX
bool avx2;
bool avx512f;
bool sha;
bool fsrm;
};
extern const CPUIDRegisters CPUID;
#endif
/**
* 256 zero bits / 32 zero bytes
*/
extern const uint64_t ZERO256[4];
/**
* Hexadecimal characters 0-f
*/
extern const char HEXCHARS[16];
/**
* A random integer generated at startup for Map's hash bucket calculation.
*/
extern const uint64_t s_mapNonce;
/**
* Lock memory to prevent swapping out to secondary storage (if possible)
*
* This is used to attempt to prevent the swapping out of long-term stored secure
* credentials like secret keys. It isn't supported on all platforms and may not
* be absolutely guaranteed to work, but it's a countermeasure.
*
* @param p Memory to lock
* @param l Size of memory
*/
static ZT_INLINE void memoryLock(const void *const p, const unsigned int l) noexcept
{
#ifndef __WINDOWS__
mlock(p, l);
#endif
}
/**
* Unlock memory locked with memoryLock()
*
* @param p Memory to unlock
* @param l Size of memory
*/
static ZT_INLINE void memoryUnlock(const void *const p, const unsigned int l) noexcept
{
#ifndef __WINDOWS__
munlock(p, l);
#endif
}
/**
* Perform a time-invariant binary comparison
*
* @param a First binary string
* @param b Second binary string
* @param len Length of strings
* @return True if strings are equal
*/
bool secureEq(const void *a, const void *b, unsigned int len) noexcept;
/**
* Be absolutely sure to zero memory
*
* This uses some hacks to be totally sure the compiler does not optimize it out.
*
* @param ptr Memory to zero
* @param len Length of memory in bytes
*/
void burn(void *ptr, unsigned int len);
/**
* @param n Number to convert
* @param s Buffer, at least 24 bytes in size
* @return String containing 'n' in base 10 form
*/
char *decimal(unsigned long n, char s[24]) noexcept;
/**
* Convert an unsigned integer into hex
*
* The returned pointer won't point to the start of 'buf', since
* hex writing is done in reverse order.
*
* @param i Any unsigned integer
* @param s Buffer to receive hex, must be at least (2*sizeof(i))+1 in size or overflow will occur.
* @return Pointer to s containing hex string with trailing zero byte
*/
char *hex(uint64_t i, char buf[17]) noexcept;
/**
* Decode an unsigned integer in hex format
*
* @param s String to decode, non-hex chars are ignored
* @return Unsigned integer
*/
uint64_t unhex(const char *s) noexcept;
/**
* Convert a byte array into hex
*
* @param d Bytes
* @param l Length of bytes
* @param s String buffer, must be at least (l*2)+1 in size or overflow will occur
* @return Pointer to filled string buffer
*/
char *hex(const void *d, unsigned int l, char *s) noexcept;
/**
* Decode a hex string
*
* @param h Hex C-string (non hex chars are ignored)
* @param hlen Maximum length of string (will stop at terminating zero)
* @param buf Output buffer
* @param buflen Length of output buffer
* @return Number of written bytes
*/
unsigned int unhex(const char *h, unsigned int hlen, void *buf, unsigned int buflen) noexcept;
/**
* Generate secure random bytes
*
* This will try to use whatever OS sources of entropy are available. It's
* guarded by an internal mutex so it's thread-safe.
*
* @param buf Buffer to fill
* @param bytes Number of random bytes to generate
*/
void getSecureRandom(void *buf, unsigned int bytes) noexcept;
/**
* @return Secure random 64-bit integer
*/
uint64_t getSecureRandomU64() noexcept;
/**
* Encode string to base32
*
* @param data Binary data to encode
* @param length Length of data in bytes
* @param result Result buffer
* @param bufSize Size of result buffer
* @return Number of bytes written
*/
int b32e(const uint8_t *data, int length, char *result, int bufSize) noexcept;
/**
* Decode base32 string
*
* @param encoded C-string in base32 format (non-base32 characters are ignored)
* @param result Result buffer
* @param bufSize Size of result buffer
* @return Number of bytes written or -1 on error
*/
int b32d(const char *encoded, uint8_t *result, int bufSize) noexcept;
/**
* Get a non-cryptographic random integer.
*
* This should never be used for cryptographic use cases, not even for choosing
* message nonce/IV values if they should not repeat. It should only be used when
* a fast and potentially "dirty" random source is needed.
*/
uint64_t random() noexcept;
/**
* Perform a safe C string copy, ALWAYS null-terminating the result
*
* This will never ever EVER result in dest[] not being null-terminated
* regardless of any input parameter (other than len==0 which is invalid).
*
* @param dest Destination buffer (must not be NULL)
* @param len Length of dest[] (if zero, false is returned and nothing happens)
* @param src Source string (if NULL, dest will receive a zero-length string and true is returned)
* @return True on success, false on overflow (buffer will still be 0-terminated)
*/
bool scopy(char *dest, unsigned int len, const char *src) noexcept;
/**
* Mix bits in a 64-bit integer (non-cryptographic, for hash tables)
*
* https://nullprogram.com/blog/2018/07/31/
*
* @param x Integer to mix
* @return Hashed value
*/
static ZT_INLINE uint64_t hash64(uint64_t x) noexcept
{
x ^= x >> 30U;
x *= 0xbf58476d1ce4e5b9ULL;
x ^= x >> 27U;
x *= 0x94d049bb133111ebULL;
x ^= x >> 31U;
return x;
}
/**
* Mix bits in a 32-bit integer (non-cryptographic, for hash tables)
*
* https://nullprogram.com/blog/2018/07/31/
*
* @param x Integer to mix
* @return Hashed value
*/
static ZT_INLINE uint32_t hash32(uint32_t x) noexcept
{
x ^= x >> 16U;
x *= 0x7feb352dU;
x ^= x >> 15U;
x *= 0x846ca68bU;
x ^= x >> 16U;
return x;
}
/**
* Check if a buffer's contents are all zero
*/
static ZT_INLINE bool allZero(const void *const b, unsigned int l) noexcept
{
const uint8_t *p = reinterpret_cast<const uint8_t *>(b);
#ifndef ZT_NO_UNALIGNED_ACCESS
while (l >= 8) {
if (*reinterpret_cast<const uint64_t *>(p) != 0)
return false;
p += 8;
l -= 8;
}
#endif
for (unsigned int i = 0; i < l; ++i) {
if (reinterpret_cast<const uint8_t *>(p)[i] != 0)
return false;
}
return true;
}
/**
* Wrapper around reentrant strtok functions, which differ in name by platform
*
* @param str String to tokenize or NULL for subsequent calls
* @param delim Delimiter
* @param saveptr Pointer to pointer where function can save state
* @return Next token or NULL if none
*/
static ZT_INLINE char *stok(char *str, const char *delim, char **saveptr) noexcept
{
#ifdef __WINDOWS__
return strtok_s(str,delim,saveptr);
#else
return strtok_r(str, delim, saveptr);
#endif
}
static ZT_INLINE unsigned int strToUInt(const char *s) noexcept
{
return (unsigned int)strtoul(s, nullptr, 10);
}
static ZT_INLINE unsigned long long hexStrToU64(const char *s) noexcept
{
#ifdef __WINDOWS__
return (unsigned long long)_strtoui64(s,nullptr,16);
#else
return strtoull(s, nullptr, 16);
#endif
}
/**
* Compute 32-bit FNV-1a checksum
*
* See: http://www.isthe.com/chongo/tech/comp/fnv/
*
* @param data Data to checksum
* @param len Length of data
* @return FNV1a checksum
*/
static ZT_INLINE uint32_t fnv1a32(const void *const data, const unsigned int len) noexcept
{
uint32_t h = 0x811c9dc5;
const uint32_t p = 0x01000193;
for (unsigned int i = 0; i < len; ++i)
h = (h ^ (uint32_t)reinterpret_cast<const uint8_t *>(data)[i]) * p;
return h;
}
#ifdef __GNUC__
static ZT_INLINE unsigned int countBits(const uint8_t v) noexcept
{ return (unsigned int)__builtin_popcount((unsigned int)v); }
static ZT_INLINE unsigned int countBits(const uint16_t v) noexcept
{ return (unsigned int)__builtin_popcount((unsigned int)v); }
static ZT_INLINE unsigned int countBits(const uint32_t v) noexcept
{ return (unsigned int)__builtin_popcountl((unsigned long)v); }
static ZT_INLINE unsigned int countBits(const uint64_t v) noexcept
{ return (unsigned int)__builtin_popcountll((unsigned long long)v); }
#else
template<typename T>
static ZT_INLINE unsigned int countBits(T v) noexcept
{
v = v - ((v >> 1) & (T)~(T)0/3);
v = (v & (T)~(T)0/15*3) + ((v >> 2) & (T)~(T)0/15*3);
v = (v + (v >> 4)) & (T)~(T)0/255*15;
return (unsigned int)((v * ((~((T)0))/((T)255))) >> ((sizeof(T) - 1) * 8));
}
#endif
/**
* Unconditionally swap bytes regardless of host byte order
*
* @param n Integer to swap
* @return Integer with bytes reversed
*/
static ZT_INLINE uint64_t swapBytes(const uint64_t n) noexcept
{
#ifdef __GNUC__
return __builtin_bswap64(n);
#else
#ifdef _MSC_VER
return (uint64_t)_byteswap_uint64((unsigned __int64)n);
#else
return (
((n & 0x00000000000000ffULL) << 56) |
((n & 0x000000000000ff00ULL) << 40) |
((n & 0x0000000000ff0000ULL) << 24) |
((n & 0x00000000ff000000ULL) << 8) |
((n & 0x000000ff00000000ULL) >> 8) |
((n & 0x0000ff0000000000ULL) >> 24) |
((n & 0x00ff000000000000ULL) >> 40) |
((n & 0xff00000000000000ULL) >> 56)
);
#endif
#endif
}
/**
* Unconditionally swap bytes regardless of host byte order
*
* @param n Integer to swap
* @return Integer with bytes reversed
*/
static ZT_INLINE uint32_t swapBytes(const uint32_t n) noexcept
{
#if defined(__GNUC__)
return __builtin_bswap32(n);
#else
#ifdef _MSC_VER
return (uint32_t)_byteswap_ulong((unsigned long)n);
#else
return htonl(n);
#endif
#endif
}
/**
* Unconditionally swap bytes regardless of host byte order
*
* @param n Integer to swap
* @return Integer with bytes reversed
*/
static ZT_INLINE uint16_t swapBytes(const uint16_t n) noexcept
{
#if defined(__GNUC__)
return __builtin_bswap16(n);
#else
#ifdef _MSC_VER
return (uint16_t)_byteswap_ushort((unsigned short)n);
#else
return htons(n);
#endif
#endif
}
// These are helper adapters to load and swap integer types special cased by size
// to work with all typedef'd variants, signed/unsigned, etc.
template< typename I, unsigned int S >
class _swap_bytes_bysize;
template< typename I >
class _swap_bytes_bysize< I, 1 >
{
public:
static ZT_INLINE I s(const I n) noexcept
{ return n; }
};
template< typename I >
class _swap_bytes_bysize< I, 2 >
{
public:
static ZT_INLINE I s(const I n) noexcept
{ return (I)swapBytes((uint16_t)n); }
};
template< typename I >
class _swap_bytes_bysize< I, 4 >
{
public:
static ZT_INLINE I s(const I n) noexcept
{ return (I)swapBytes((uint32_t)n); }
};
template< typename I >
class _swap_bytes_bysize< I, 8 >
{
public:
static ZT_INLINE I s(const I n) noexcept
{ return (I)swapBytes((uint64_t)n); }
};
template< typename I, unsigned int S >
class _load_be_bysize;
template< typename I >
class _load_be_bysize< I, 1 >
{
public:
static ZT_INLINE I l(const uint8_t *const p) noexcept
{ return p[0]; }
};
template< typename I >
class _load_be_bysize< I, 2 >
{
public:
static ZT_INLINE I l(const uint8_t *const p) noexcept
{ return (I)(((unsigned int)p[0] << 8U) | (unsigned int)p[1]); }
};
template< typename I >
class _load_be_bysize< I, 4 >
{
public:
static ZT_INLINE I l(const uint8_t *const p) noexcept
{ return (I)(((uint32_t)p[0] << 24U) | ((uint32_t)p[1] << 16U) | ((uint32_t)p[2] << 8U) | (uint32_t)p[3]); }
};
template< typename I >
class _load_be_bysize< I, 8 >
{
public:
static ZT_INLINE I l(const uint8_t *const p) noexcept
{ return (I)(((uint64_t)p[0] << 56U) | ((uint64_t)p[1] << 48U) | ((uint64_t)p[2] << 40U) | ((uint64_t)p[3] << 32U) | ((uint64_t)p[4] << 24U) | ((uint64_t)p[5] << 16U) | ((uint64_t)p[6] << 8U) | (uint64_t)p[7]); }
};
template< typename I, unsigned int S >
class _load_le_bysize;
template< typename I >
class _load_le_bysize< I, 1 >
{
public:
static ZT_INLINE I l(const uint8_t *const p) noexcept
{ return p[0]; }
};
template< typename I >
class _load_le_bysize< I, 2 >
{
public:
static ZT_INLINE I l(const uint8_t *const p) noexcept
{ return (I)((unsigned int)p[0] | ((unsigned int)p[1] << 8U)); }
};
template< typename I >
class _load_le_bysize< I, 4 >
{
public:
static ZT_INLINE I l(const uint8_t *const p) noexcept
{ return (I)((uint32_t)p[0] | ((uint32_t)p[1] << 8U) | ((uint32_t)p[2] << 16U) | ((uint32_t)p[3] << 24U)); }
};
template< typename I >
class _load_le_bysize< I, 8 >
{
public:
static ZT_INLINE I l(const uint8_t *const p) noexcept
{ return (I)((uint64_t)p[0] | ((uint64_t)p[1] << 8U) | ((uint64_t)p[2] << 16U) | ((uint64_t)p[3] << 24U) | ((uint64_t)p[4] << 32U) | ((uint64_t)p[5] << 40U) | ((uint64_t)p[6] << 48U) | ((uint64_t)p[7]) << 56U); }
};
/**
* Convert any signed or unsigned integer type to big-endian ("network") byte order
*
* @tparam I Integer type (usually inferred)
* @param n Value to convert
* @return Value in big-endian order
*/
template< typename I >
static ZT_INLINE I hton(const I n) noexcept
{
#if __BYTE_ORDER == __LITTLE_ENDIAN
return _swap_bytes_bysize< I, sizeof(I) >::s(n);
#else
return n;
#endif
}
/**
* Convert any signed or unsigned integer type to host byte order from big-endian ("network") byte order
*
* @tparam I Integer type (usually inferred)
* @param n Value to convert
* @return Value in host byte order
*/
template< typename I >
static ZT_INLINE I ntoh(const I n) noexcept
{
#if __BYTE_ORDER == __LITTLE_ENDIAN
return _swap_bytes_bysize< I, sizeof(I) >::s(n);
#else
return n;
#endif
}
/**
* Copy bits from memory into an integer type without modifying their order
*
* @tparam I Type to load
* @param p Byte stream, must be at least sizeof(I) in size
* @return Loaded raw integer
*/
template< typename I >
static ZT_INLINE I loadAsIsEndian(const void *const p) noexcept
{
#ifdef ZT_NO_UNALIGNED_ACCESS
I tmp;
for(int i=0;i<(int)sizeof(I);++i)
reinterpret_cast<uint8_t *>(&tmp)[i] = reinterpret_cast<const uint8_t *>(p)[i];
return tmp;
#else
return *reinterpret_cast<const I *>(p);
#endif
}
/**
* Copy bits from memory into an integer type without modifying their order
*
* @tparam I Type to store
* @param p Byte array (must be at least sizeof(I))
* @param i Integer to store
*/
template< typename I >
static ZT_INLINE void storeAsIsEndian(void *const p, const I i) noexcept
{
#ifdef ZT_NO_UNALIGNED_ACCESS
for(unsigned int k=0;k<sizeof(I);++k)
reinterpret_cast<uint8_t *>(p)[k] = reinterpret_cast<const uint8_t *>(&i)[k];
#else
*reinterpret_cast<I *>(p) = i;
#endif
}
/**
* Decode a big-endian value from a byte stream
*
* @tparam I Type to decode (should be unsigned e.g. uint32_t or uint64_t)
* @param p Byte stream, must be at least sizeof(I) in size
* @return Decoded integer
*/
template< typename I >
static ZT_INLINE I loadBigEndian(const void *const p) noexcept
{
#ifdef ZT_NO_UNALIGNED_ACCESS
return _load_be_bysize<I,sizeof(I)>::l(reinterpret_cast<const uint8_t *>(p));
#else
return ntoh(*reinterpret_cast<const I *>(p));
#endif
}
/**
* Save an integer in big-endian format
*
* @tparam I Integer type to store (usually inferred)
* @param p Byte stream to write (must be at least sizeof(I))
* #param i Integer to write
*/
template< typename I >
static ZT_INLINE void storeBigEndian(void *const p, I i) noexcept
{
#ifdef ZT_NO_UNALIGNED_ACCESS
storeAsIsEndian(p,hton(i));
#else
*reinterpret_cast<I *>(p) = hton(i);
#endif
}
/**
* Decode a little-endian value from a byte stream
*
* @tparam I Type to decode
* @param p Byte stream, must be at least sizeof(I) in size
* @return Decoded integer
*/
template< typename I >
static ZT_INLINE I loadLittleEndian(const void *const p) noexcept
{
#if __BYTE_ORDER == __BIG_ENDIAN || defined(ZT_NO_UNALIGNED_ACCESS)
return _load_le_bysize<I,sizeof(I)>::l(reinterpret_cast<const uint8_t *>(p));
#else
return *reinterpret_cast<const I *>(p);
#endif
}
/**
* Save an integer in little-endian format
*
* @tparam I Integer type to store (usually inferred)
* @param p Byte stream to write (must be at least sizeof(I))
* #param i Integer to write
*/
template< typename I >
static ZT_INLINE void storeLittleEndian(void *const p, const I i) noexcept
{
#if __BYTE_ORDER == __BIG_ENDIAN
storeAsIsEndian(p,_swap_bytes_bysize<I,sizeof(I)>::s(i));
#else
#ifdef ZT_NO_UNALIGNED_ACCESS
storeAsIsEndian(p,i);
#else
*reinterpret_cast<I *>(p) = i;
#endif
#endif
}
/**
* Copy memory block whose size is known at compile time.
*
* @tparam L Size of memory
* @param dest Destination memory
* @param src Source memory
*/
template< unsigned int L >
static ZT_INLINE void copy(void *const dest, const void *const src) noexcept
{
#ifdef ZT_ARCH_X64
uint8_t *volatile d = reinterpret_cast<uint8_t *>(dest);
const uint8_t *s = reinterpret_cast<const uint8_t *>(src);
for (unsigned int i = 0; i < (L >> 6U); ++i) {
__m128i x0 = _mm_loadu_si128(reinterpret_cast<const __m128i *>(s));
__m128i x1 = _mm_loadu_si128(reinterpret_cast<const __m128i *>(s + 16));
__m128i x2 = _mm_loadu_si128(reinterpret_cast<const __m128i *>(s + 32));
__m128i x3 = _mm_loadu_si128(reinterpret_cast<const __m128i *>(s + 48));
s += 64;
_mm_storeu_si128(reinterpret_cast<__m128i *>(d), x0);
_mm_storeu_si128(reinterpret_cast<__m128i *>(d + 16), x1);
_mm_storeu_si128(reinterpret_cast<__m128i *>(d + 32), x2);
_mm_storeu_si128(reinterpret_cast<__m128i *>(d + 48), x3);
d += 64;
}
if ((L & 32U) != 0) {
__m128i x0 = _mm_loadu_si128(reinterpret_cast<const __m128i *>(s));
__m128i x1 = _mm_loadu_si128(reinterpret_cast<const __m128i *>(s + 16));
s += 32;
_mm_storeu_si128(reinterpret_cast<__m128i *>(d), x0);
_mm_storeu_si128(reinterpret_cast<__m128i *>(d + 16), x1);
d += 32;
}
if ((L & 16U) != 0) {
__m128i x0 = _mm_loadu_si128(reinterpret_cast<const __m128i *>(s));
s += 16;
_mm_storeu_si128(reinterpret_cast<__m128i *>(d), x0);
d += 16;
}
if ((L & 8U) != 0) {
*reinterpret_cast<volatile uint64_t *>(d) = *reinterpret_cast<const uint64_t *>(s);
s += 8;
d += 8;
}
if ((L & 4U) != 0) {
*reinterpret_cast<volatile uint32_t *>(d) = *reinterpret_cast<const uint32_t *>(s);
s += 4;
d += 4;
}
if ((L & 2U) != 0) {
*reinterpret_cast<volatile uint16_t *>(d) = *reinterpret_cast<const uint16_t *>(s);
s += 2;
d += 2;
}
if ((L & 1U) != 0) {
*d = *s;
}
#else
memcpy(dest,src,L);
#endif
}
/**
* Copy memory block whose size is known at run time
*
* @param dest Destination memory
* @param src Source memory
* @param len Bytes to copy
*/
static ZT_INLINE void copy(void *const dest, const void *const src, unsigned int len) noexcept
{ memcpy(dest, src, len); }
/**
* Zero memory block whose size is known at compile time
*
* @tparam L Size in bytes
* @param dest Memory to zero
*/
template< unsigned int L >
static ZT_INLINE void zero(void *const dest) noexcept
{
#ifdef ZT_ARCH_X64
uint8_t *volatile d = reinterpret_cast<uint8_t *>(dest);
__m128i z = _mm_setzero_si128();
for (unsigned int i = 0; i < (L >> 6U); ++i) {
_mm_storeu_si128(reinterpret_cast<__m128i *>(d), z);
_mm_storeu_si128(reinterpret_cast<__m128i *>(d + 16), z);
_mm_storeu_si128(reinterpret_cast<__m128i *>(d + 32), z);
_mm_storeu_si128(reinterpret_cast<__m128i *>(d + 48), z);
d += 64;
}
if ((L & 32U) != 0) {
_mm_storeu_si128(reinterpret_cast<__m128i *>(d), z);
_mm_storeu_si128(reinterpret_cast<__m128i *>(d + 16), z);
d += 32;
}
if ((L & 16U) != 0) {
_mm_storeu_si128(reinterpret_cast<__m128i *>(d), z);
d += 16;
}
if ((L & 8U) != 0) {
*reinterpret_cast<volatile uint64_t *>(d) = 0;
d += 8;
}
if ((L & 4U) != 0) {
*reinterpret_cast<volatile uint32_t *>(d) = 0;
d += 4;
}
if ((L & 2U) != 0) {
*reinterpret_cast<volatile uint16_t *>(d) = 0;
d += 2;
}
if ((L & 1U) != 0) {
*d = 0;
}
#else
memset(dest,0,L);
#endif
}
/**
* Zero memory block whose size is known at run time
*
* @param dest Memory to zero
* @param len Size in bytes
*/
static ZT_INLINE void zero(void *const dest, const unsigned int len) noexcept
{ memset(dest, 0, len); }
/**
* Simple malloc/free based C++ STL allocator.
*
* This is used to make sure our containers don't use weird libc++
* allocators but instead use whatever malloc() is, which in turn
* can be overridden by things like jemaclloc or tcmalloc.
*
* @tparam T Allocated type
*/
template< typename T >
struct Mallocator
{
typedef size_t size_type;
typedef ptrdiff_t difference_type;
typedef T *pointer;
typedef const T *const_pointer;
typedef T &reference;
typedef const T &const_reference;
typedef T value_type;
template< class U >
struct rebind
{
typedef Mallocator< U > other;
};
ZT_INLINE Mallocator() noexcept
{}
ZT_INLINE Mallocator(const Mallocator &) noexcept
{}
template< class U >
ZT_INLINE Mallocator(const Mallocator< U > &) noexcept
{}
ZT_INLINE ~Mallocator() noexcept
{}
ZT_INLINE pointer allocate(size_type s, void const * = nullptr)
{
if (0 == s)
return nullptr;
pointer temp = (pointer)malloc(s * sizeof(T));
if (temp == nullptr)
throw std::bad_alloc();
return temp;
}
ZT_INLINE pointer address(reference x) const
{ return &x; }
ZT_INLINE const_pointer address(const_reference x) const
{ return &x; }
ZT_INLINE void deallocate(pointer p, size_type)
{ free(p); }
ZT_INLINE size_type max_size() const noexcept
{ return std::numeric_limits< size_t >::max() / sizeof(T); }
ZT_INLINE void construct(pointer p, const T &val)
{ new((void *)p) T(val); }
ZT_INLINE void destroy(pointer p)
{ p->~T(); }
constexpr bool operator==(const Mallocator &) const noexcept
{ return true; }
constexpr bool operator!=(const Mallocator &) const noexcept
{ return false; }
};
} // namespace Utils
} // namespace ZeroTier
#endif